What instruction controls the sequence of operations in a continuous-cycle PLC program?

The coil instruction is fundamental in a PLC (Programmable Logic Controller) program because it directly controls the output operations based on the logical conditions established in the program. By setting or resetting the states of coils, the PLC can execute a sequence of operations that is essential for continuous processes. The coil instruction essentially acts as a relay that signifies whether a device, motor, valve, or any other output should be activated or deactivated.

In the context of a continuous-cycle PLC program, the coil instruction dictates the flow of the program by determining which operations should take place at any given time based on various conditions. By controlling the coils, a programmer can establish a systematic sequence that ensures the proper functioning of machinery or processes in real-time environments.

Other types of instructions, such as timer, counter, or input instructions, do not directly manage the primary operations of the program. While they serve important roles—for instance, timers can trigger actions after a specified duration, counters can keep track of occurrences, and input instructions reflect the state of physical sensors—the coil instruction is key to managing the overall sequence of operations in the program.